Truck fuel tanks typically are fabricated from multiple pieces of metal, such as steel or aluminum. The sheet of metal typically first is sheared to a rectangular shape, and then is punched or laser cut to form holes in the sheet. The sheet then is rolled into a cylinder, a “D” shape or a rectangular shape, and then welded along the longitudinal seam. The tank ends typically are formed from aluminum sheets which are welded to the built-up, i.e., rolled shell. In a final step, fittings for fuel fill, fuel drain, fuel vent, fuel suction and fuel return tubes are welded into place on the shell or on the tank ends.
This process has a number of challenges. One challenge occurs at the “T’ weld joint, i.e., the location where the longitudinal seam and the circumferential seam head welds overlap. This location at the seam overlap region experiences a large number of leaks. Moreover, the overall process of welded metal fuel tank construction is very labor intensive Efforts to automate the welding process by using robotic welders has been somewhat successful in reducing the number of leaks in these tank. However, in general, tank manufacturers have a difficult time being commercially viable due to the capital intensity of the welding operation and due to the low price that the final product purchasers are willing to pay for the finished product.
There is a need, therefore, for a fuel tank with reduced probability of leaks and for a method of manufacturing a tank that is more cost effective.